1. Field of the Invention
The present invention relates to a semiconductor light-emitting device provided with a semiconductor light-emitting element.
2. Description of the Related Art
FIGS. 6 and 7 illustrate an example of conventional semiconductor light-emitting device (see JP-A-2005-353914, for example). The illustrated semiconductor light-emitting device X includes a lead frame 91, an LED chip 92, a case 93, and a transparent resin 94. The lead frame 91 includes two strip portions, i.e., a relatively long portion 91a and a relatively short portion 91b, as seen from FIG. 6. These two portions, having the same width as seen from FIG. 7, are fitted into a lower space in the case 93 in a manner such that the bottom surface of the lead frame 91 is exposed out of the case 93. The LED chip 92 serves as a light source of the semiconductor light-emitting device X, and is bonded to the longer strip portion 91a of the lead frame 91. The LED chip 92 is connected to the shorter strip portion 91b of the lead frame 91 via a wire 95. The light-emitting device X may be mounted on a printed circuit board, for example.
In order to obtain stronger light emission from the semiconductor light-emitting device X, it is required to apply greater electrical power to the LED chip 92. Inevitably, the amount of heat generated by the LED chip 92 is increased, and for maintaining the proper light emission, the heat should be conducted from the longer strip portion 91a to the circuit board. One way to facilitate the heat conduction is to broaden the strip portion 91a (hence the lead frame 91) to which the LED chip 92 is attached. While the width of the longer strip portion 91a is to be increased, the overall size of the case 93 may be unchanged so that the light-emitting device X is kept compact. In this case, the side walls of the case 93 need to be made thinner to permit the size increase of the longer strip portion 91a. This configuration, however, will weaken the frame-holding force of the case 93, which may allow the lead frame 91 to drop off from the case 93.